FromM3toAMG

Today i replaced my spark plugs aswell as installed new K&N filters and removed my carbon filters.. now my car will randomly sputter like its misfiring or something when accelerating. this has only happens at freeway speeds, when on city streets the car performs fine. I installed all the plugs correctly with a 0.040 Gap which is what the plugs i removed were set to. Does the ECU need to adjust at all to the better air flow? it seems to be occurring less with the more i drive, if this was an issue with the spark plugs or a coil it would be a constant issue, correct? also wouldn't it throw a CEL if it was an issue with the plugs i installed?

viren.89

I've read often that once people remove the cabin filters , they face issues.

Free diagnosis would be trying driving whilst having them back in

03'55AMG

I have seen exact similar symptoms on other cars, where a tune up caused a slight miss. The fix was usually a slightly larger plug gap.

FromM3toAMG

I don't get how that works..that's like saying that every time you remove a spark plug you have to change the gap.. Not disputing what you said just saying it doesn't make sense.. Not to mention I'm not going to repeatedly remove my spark plugs until I find the ideal gaping.

Does anyone know if this is more related to the new filters and removal of carbon filters? Again I feel like if this was an issue with my spark plugs it would be consistent.. I know with BMW the ECUs are adaptive, are MBs the same? Like I said before the more I drive the less it does it.. BTW I haven't had a chance to put my carbon filters back in... But I can say I do notice a power increase.

03'55AMG

Yea I don't think it makes any sense either, but it works like a charm on Hondas with higher mileage

StarvingArtist

Yes. adaptive ECU. It will have to relearn at different temperatures also.

Yacht Master

Google "K&N car sputters"

FromM3toAMG

Any idea how long this will take? Will disconnecting the battery and resetting anything help? The obvious solution is to put the filters back in, but I don't want them and if the car will eventually adjust I'll wait it out. I'm just worried I may be causing damage.

FromM3toAMG

Holy **** I'm dumb.. I just realized what the issue is.. I forgot to tighten the metal clasps on the upper portion of the intake.. THAT is why it's sputtering, it's gotta be. I'm sorry guys.. I'm dumb lol....wow... Ha oops

chawkins2001

It's the k&N filters been the main culprit. Seen it many times before.

FromM3toAMG

Correct, K&Ns where the issue. Stock filters are back in,along with my carbon filters.. car appears to be back to normal.